Diflubenzuron (Ref: OMS 1804)

Diflubenzuron (Ref: OMS 1804)	Last updated: 13/01/2021
(Also known as: DFB; difluron; ENT 29054)

SUMMARY

Diflubenzuron is a urea-derived insecticide that is approved for use in the EU. It has a low aqueous solubility and is volatile. Based on its chemical properties, it is not expected to leach to groundwater. It is not persistent in soils but can be in water in some circumstances. It has a low mammalian toxicity. It is moderately toxic to fish, honeybees and earthworms but more toxic to aquatic invertebrates. Diflubenzuron is relatively non-toxic to birds and algae

GENERAL INFORMATION

Description

A persistent urea derivative insecticide used to control a wide range of leaf-eating insects

Example pests controlled

Scararid flies; Armyworms; Leafminers, Whiteflies; Termites; Fungus gnats; Shore flies

Example applications

Ornamentals in greenhouses, shadehouses and commercial structures; Building protection from termite colonies; Fruit

Efficacy & activity

Efficiacy has been shown via extensive use.

Availability status

Current

Introduction & key dates

1972, first reported; 1975, first introduced

UK regulatory status

UK COPR regulatory status

Phasing out

Date COPR inclusion expires

Expired

UK LERAP status

Buffer probably required in UK - see product label

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Greece/Slovakia

Date EC 1107/2009 inclusion expires

Expired

EU Candidate for substitution (CfS)

Listed in EU database

Yes

Approved for use (✓) under EC 1107/2009 in the following EU Member States

ATAustria	BEBelgium	BGBulgaria	CYCyprus	CZCzech Republic	DEGermany	DKDenmark	EEEstonia	ELGreece
	✓	✓	✓	✓				✓
ESSpain	FIFinland	FRFrance	HRCroatia	HUHungary	IEIreland	ITItaly	LTLithuania	LULuxembourg
✓		✓	✓	✓
LVLatvia	MTMalta	NLNetherlands	PLPoland	PTPortugal	RORomania	SESweden	SISlovenia	SKSlovakia
		✓	✓	✓	✓			✓

Also used in

Australia, USA

Chemical structure

Isomerism

Chemical formula

C₁₄H₉ClF₂N₂O₂

Canonical SMILES

C1=CC(=C(C(=C1)F)C(=O)NC(=O)NC2=CC=C(C=C2)Cl)F

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

QQQYTWIFVNKMRW-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H9ClF2N2O2/c15-8-4-6-9(7-5-8)18-14(21)19-13(20)12-10(16)2-1-3-11(12)17/h1-7H,(H2,18,19,20,21)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
diflubenzuron	-

General status

Pesticide type

Insecticide

Substance group

Benzoylurea

Minimum active substance purity

950 g kg⁻¹

Known relevant impurities

EU dossier: 4-chloroaniline

Substance origin

Synthetic

Mode of action

Selective, non-systemic with contact and stomach action, acts by inhibiting chitin synthesis

CAS RN

35367-38-5

EC number

252-529-3

CIPAC number

339

US EPA chemical code

108201

PubChem CID

37123

Molecular mass

310.68

PIN (Preferred Identification Name)

N-[(4-chlorophenyl)carbamoyl]-2,6-difluorobenzamide

IUPAC name

1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea

CAS name

N-(((4-chlorophenyl)amino)carbonyl)-2,6-difluorobenzamide

Other status information

Relevant Environmental Water Quality Standards

UK Environment Agency non-statutory standard for the protection of aquatic life in freshwater annual average 0.001 µg l⁻¹, max acceptable conc 0.015 µg l⁻¹
UK Environment Agency non-statutory standard for the protection of aquatic life in saltwater annual average 0.005 µg l⁻¹, max acceptable conc 0.01 µg l⁻¹

Herbicide Resistance Classification (HRAC)

Not applicable

Herbicide Resistance Classification (WSSA)

Not applicable

Insecticide Resistance Classification (IRAC)

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Cydia pomonella, Plutella xylostella, Spodoptera littoralis, Lucilia cuprina, Spodoptera exigua

Physical state

White crystalline solid

Formulations

Property

Value

Example manufacturers & suppliers of products using this active now or historically

Dimilin Flo
Dimilin WG-80
Astonex

Example products using this active

Certis
Chemtura
Duphar

Formulation and application details

Supplied in a variety of formulations including wettable powders, oil-dispersable concentrates and granules

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

0.08

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

6980

Acetone

n-Hexane

290

Toluene

1100

Methanol

Melting point (°C)

227.6

Boiling point (°C)

Decomposes before boiling at normal pressure

Degradation point (°C)

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

Octanol-water partition coefficient at pH 7, 20 °C

7.76 X 10⁰³

Calculated

Log P

3.89

High

Bulk density (g ml⁻¹)

1.57

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.00012

Low volatility

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

4.70 X 10^-04

Non-volatile

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

In acetonitrile 257nm = 15148, 290nm = 10500

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Non-persistent

DT₅₀ (lab at 20 °C)

3.2

Non-persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 2.0-6.7 days

Dissipation rate RL₅₀ on plant matrix

Value

14.2

Note

Published literature RL₅₀ range 7.9-23.7 days, 2 field crops, various matrices, n=3

Dissipation rate RL₅₀ on and in plant matrix

Value

11.7

Note

Published literature RL₅₀ range 2.8-21.0 days, 4 field & undercover grown crops, various matrices, n=4

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

Not a significant degradation route

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Moderately persistent

Note

Stable pH 5 to pH 7, some hydrolysis at pH 9

Water-sediment DT₅₀ (days)

4.5

Fast

Water phase only DT₅₀ (days)

3.0

Moderately fast

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

K_oc

Notes and range

Freundlich

K_f

65.2

Non-mobile

K_foc

4620

¹/_n

1.1

Notes and range

EU dossier K_f range 34.2-97.7 mL g⁻¹, K_foc range 1983-6918 mL g⁻¹, ¹/_n range 0.97-1.22, Soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.17

Calculated

Low leachability

SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate

Value

1.26 X 10^-03

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Non-mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

4-chlorophenylurea

Soil

0.308

Major fraction, Relevant

2,6-difluorobenzoic acid

Soil

0.133

Major fraction, Relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

4-chloroaniline
Note: Mutagenic

PCA

Plant; Animal

4-chloroacetanilide

PCAA

Animal

2,6-difluorobenzamide

DFBAM

Rat; Animal (Milk)

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

320

(Other literature Log BCF range 2.9-3.6 (R3))

Threshold for concern

CT₅₀ (days)

0.6

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 4640

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

> 3200

Unknown species Reproductive NOAEL

Low

Birds - Acute LD₅₀ (mg kg⁻¹)

> 5000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 1206 mg kg bw⁻¹ day⁻¹

Colinus virginianus

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

42.7

Colinius virginianus NOEC

Moderate

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

> 0.13

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.2

Oncorhynchus mykiss

Moderate

Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

0.0026

Daphnia magna

High

Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

0.00004

Daphnia magna

High

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

0.0021

Americamysis bahia

High

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)

> 0.19

Lemna gibba

Moderate

Non-target plants

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

Pseudokirchneriella subcapitata

Low

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

Unknown species

Moderate

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 74.2

Apis mellifera

Moderate

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 9.1

Apis mellifera

Moderate

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

0.1

Bombus terrestris

High

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 1.46

Bombus terrestris

Moderate

Literature DT₅₀ values range 0.06- 5.11 µg bee⁻¹ depending upon exposure time, 1-7 days

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other pollinators (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other pollinators (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

> 500

Eisenia foetida corr

Moderate

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

500

Eisenia foetida 56 day corr

Low

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

0.165

Folsomia candida 28d corr

Other arthropod (1)

LR₅₀ g ha⁻¹

% Effect

Harmless

[Dose: 300 g ha⁻¹]
Typhlodromus pyri

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Harmful

[Dose: 300 g ha⁻¹]
Chrysoperla carnea

Soil micro-organisms

Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect

Dose: 0.75 kg ha⁻¹

Mesocosm study data

NOEAEC mg l⁻¹

0.00007

Zooplankton EAC

NOEAEC mg l⁻¹

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 4640

Rat

Low

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2000

Rabbit

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 2.5

Rat 4 hr (nose only dust)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

0.1

Dog SF=100

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

None allocated

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

0.033

Dog SF=100

Dermal penetration studies (%)

0.2-13

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks identified

Occupational

Acceptable risks for proposed uses - PPE/PPC advised

MRLs

European

EU MRL pesticide database

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

EU Dir 89/778/EC limit; Calc MAC=60 µg l⁻¹

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

General human health issues

Reported to cause methaemoglobinaemia
Endocrine issues - Pregnane X cellular receptor activation
Possible liver & spleen toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Code is usually 9

CLP classification 2013

Health: H302, H312, H332, H373
Environment: H400, H410

EC Risk Classification

Xi - Irritant: R36
N - Dangerous for the environment: R50/53

EC Safety Classification

S2, S13, S20/21, S26, S39, S60/61

WHO Classification

III (Slightly hazardous)

UN Number

Usually 3077 or 3082

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

diflubenzuron

French

diflubenzuron

German

Diflubenzuron

Danish

diflubenzuron

Italian

diflubenzuron

Spanish

diflubenzuron

Greek

Polish

diflubenzuron

Swedish

diflubensuron

Hungarian

diflubenzuron

Dutch

diflubenzuron

Record last updated:	13/01/2021
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242